Improvement in hollow augers



i diameters,

UNITED STATES PATENT GFFICE.

`COLUMBUS W. CORR, 0F GARLINVILLE, ILLINOIS.

IMPROVEMENT IN HOLLOW UGERS.

Specification forming part lof Letters Patent No. 136,138, dated February 25, 1873.

' oning-tools 5 and consists in providing va single body or chuck with a series of interchangeable cutter-heads or bits, by which it is adapted for forming tenons of different sizes; and it also consists in a novel manner of constructing the cutter-heads from a single plate of metal, as hereinafter fully explained.

lFigure 1 is a longitudinal central section of my auger; Fig. 2, an end or face view of the same; Fig. 3, a face view of one of the cutter-heads; Fig. 4, a section of the same on the line x fr; and Fig. 5, a perspective view of the same.

In constructing my auger I first `provide a tubular body or chuck, A, of an internal diameter equal to the size of the largest tenons that will be required, and on its front endIform a large round head, a, provided with a circular recess, b, to receive the cutter-heads, and with two radial screws, c, to hold the cutterl heads in place. Having provided the body or chuck, I next provide a series of interchangeable cutters or bits, B, therefor, making them all of the proper size to iitsnugly within the recess b, but of different internal corresponding with the various sizes of tenons that may be required, so that, by exchanging the cutters, the auger may be adapted for forming tenons of different sizes. Each cutter consists of a single plate of metal of a uniform thickness of about one-eighth of an inch. In forming the cutter a central hole, d, is made through the plate of the exact size of the tenon to be produced; and then two radial slits, c, are cut outwardly from said hole, and the metal then forced upward from the back of the plate, so as to `form two semicircular inclines or faces, f,

around the hole. The raised ends of the inclines, which terminate at the slits, are beveled off on the under side, and form the knives or cutters. The chips or shavings taken oft' by the cutting edges escape through the slits e, which are made for this purpose, and -to allow the metal to bel turned up to form the cutting-edges. Each cutting-edge I provide, at its inner corner, with a cutting-lip, t, which extends through to the back of the plate at a right angle to the cutting-edge. This lip serves to sever the inner ends of the shavings from the wood, so as to produce a smooth surface on the tenon, and also to prevent the inner corner of the cutter from wearing oft in a rounded form so as to cut imperfectly.

Opposite each cutting-edge I provide the cutter with a hole or opening, k, in order to permit the ready introduction and manipulation of a file or other sharpening device. In opposite edges of the cutter I make two beveled notches, m, for the fastening-screw c of the chuck or body to bear in, so that they will press the cutter down firmly in its seat, and prevent it from turning therein.

By constructing the cutters, in the manner described, of a single piece of metal, I render them exceedingly cheap, strong, and simple, and, at the same time, light and small, so that a large assortment of them will weigh but little, and may-be packed in a small space. The central hole being made of the exactrsize of the required tenon, and left unbroken except by the two narrow slits, gives the tool a rm and steady bearing, and enables it to' cut a perfectly round and true tenon. The cutter-blades being made of the semicircular form, inclined and arranged concentric with the central opening, may be sharpened and used until worn away their entire length. Being formed solidly in the plate, they require no adjustment and cannot be displaced.

WhileIhave described the cutters as being made from a dat plate, still it is obvious that, if preferred, they may be worked out of solid metal in the same form. While the cutters are especially adaptedgfor use in my chuck or body, it is evident that they may be employed with any other suitable body, either so as to be de tachable or as a fixture thereon. It is also evident that other forms of cutters may be ernployed with my body or chuck.

My invention consists in the employment of a series ofy interchangeable cutters with a single body or chuck, and not merely in the special construction of the devices as shown and described. The single body or chuck, constructed on my plan and provided with a suitable assortment of cutters, answers all the purposes of a set or series of ordinary augers,whi1e it may beprovided at a far less cost and packed in much less space.

I am aware that bits with expansible heads are not new but they are entirely dierent from my device in construction and operation, and are susceptible of but a very limited adjustment, so that a number of them would be required to cover the same range of adjustment as one of my angers. y

Having thus described my invention, what I claim is- 1. The combination of the body or chuck A with the cutter B, constructed substantially as described, for the purpose set forth.

2. The cutter B, formed in one solid piece, having the central opening d and cuttingblades, constructed and arranged substantially as described.

COLUMBUS W. CORR.

- Witnesses:

SAMUEL PITMAN, J No. M. PALMER, Jr. 

